On using converging shock waves for pressure amplification in shock tubes

Abstract

While conventional shock tubes have a distinct advantage in dynamic calibration methods due to their inherent capability to generate pressure pulses of desired amplitude and fast rise time, they are limited to the lower levels of the pressure amplitude realization range (≤7 MPa). With the increasing need for a traceable dynamic calibration standard across wider pressure ranges, a novel technique using converging shock waves is demonstrated in this work that pushes the upper limit of the standard shock tube into the medium-high pressure range. The experiments are conducted in the shock tube facility equipped with a test section that smoothly transforms the incident plane shock into a spherical shock wave that converges, accelerates and thereby amplifies its strength many folds. The experimentally recorded pressure traces are compared with numerical simulations performed by an in-house code. Using this technique, pressure pulses with peak amplitudes in the range of 30–40 MPa, with 3.4% uncertainty based on numerical reference profile, were realized in the test section with nominal usage of resources.